Memory devices and modules

ABSTRACT

An embodiment includes a memory module, comprising: a module error interface; and a plurality of memory devices, each memory device coupled to the module error interface, including a data interface and an device error interface, and configured to communicate error information through the device error interface and the module error interface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/678,977, filed Apr. 4, 2015, which claims the benefit of U.S.Provisional Patent Application Nos. 62/039,396, filed Aug. 19, 2014,62/057,199, filed Sep. 29, 2014 and 62/075,231, filed Nov. 4, 2014, andis a continuation-in-part of U.S. patent application Ser. No.14/594,049, filed Jan. 9, 2015, and also is a continuation-in-part ofU.S. patent application Ser. No. 14/678,968, filed Apr. 4, 2015, thecontents of each are hereby incorporated by reference herein, in theirentirety, for all purposes.

BACKGROUND

This disclosure relates to memory system architectures and, inparticular, memory system architectures with error correction.

Memory controllers may be configured to perform error correction. Forexample, a memory controller may read 72 bits of data from a memorymodule where 64 bits are data and 8 bits are parity. The memorycontroller may perform other error correction techniques. Using suchtechniques, some errors in data read from the memory module may beidentified and/or corrected. In addition, the memory controller may makeinformation related to the errors available. A system including thememory controller may make operational decisions based on the errorinformation, such as retiring a memory page, halting the system, or thelike. Such a memory controller may be integrated with a processor. Forexample, Intel Xeon processors may include an integrated memorycontroller configured to perform error correction.

However, if error correction is performed before data is received by thememory controller, the error information related to the correction maynot be available in the memory controller and hence, not available tothe system for system management decisions.

SUMMARY

An embodiment includes a memory module, comprising: a module errorinterface; and a plurality of memory devices, each memory device coupledto the module error interface, including a data interface and an deviceerror interface, and configured to communicate error information throughthe device error interface and the module error interface.

Another embodiment includes a memory module, comprising: a module errorinterface; a plurality of memory devices, each memory device including adata interface and an device error interface and configured tocommunicate error information through the device error interface; and acontroller coupled to the module error interface and the device errorinterface of each memory device.

Another embodiment includes a method, comprising: receiving acommunication through a module error interface of a memory module;reading, by a controller, error information from at least one memorydevice coupled to the controller; and responding to the communicationthrough the module error interface based on the error information.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic view of a system with a memory system architectureaccording to an embodiment.

FIG. 2 is a schematic view of a system with a memory system architectureincluding a controller according to an embodiment.

FIG. 3 is a schematic view of a system with a memory system architectureincluding a baseboard management controller according to an embodiment.

FIG. 4 is a schematic view of a system with a memory system architecturewithout processor-based error correction according to an embodiment.

FIG. 5 is a schematic view of a system with a memory system architecturewith a poisoned data strobe signal according to an embodiment.

FIG. 6 is a schematic view of a system with a memory system architecturewith a separate uncorrectable error signal according to an embodiment.

FIG. 7 is a schematic view of a system with a memory system architecturewith a software module according to an embodiment.

FIG. 8 is a schematic view of a system with a memory system architecturewith an error detection and correction module according to anembodiment.

FIG. 9 is a schematic view of a system with a memory system architecturewith an aggregating module according to an embodiment.

FIG. 10 is a schematic view of a system with a memory systemarchitecture with an error correction module that aggregates informationfrom a memory control architecture module according to an embodiment.

FIG. 11 is a schematic view of a system with a memory systemarchitecture with multiple modules sharing an interface, according to anembodiment.

FIG. 12 is a schematic view of a system with a memory systemarchitecture with a correctible error module and a serial presencedetect/registering clock driver module sharing an interface according toan embodiment.

FIG. 13 is a schematic view of a system with a memory systemarchitecture with in-DRAM error correction according to an embodiment.

FIGS. 14A-D are schematic views of systems with a memory systemarchitecture with in-module error correction according to someembodiments.

FIG. 15 is a schematic view of a memory module according to anembodiment.

FIG. 16 is a schematic view of a memory module with an SPD or RCDinterface according to an embodiment.

FIG. 17 is a schematic view of a memory module with a separateuncorrectable error interface according to an embodiment.

FIG. 18 is a schematic view of a memory device according to anembodiment.

FIG. 19 is a schematic view of a memory device according to anotherembodiment.

FIG. 20 is a schematic view of a memory module including memory devicesaccording to an embodiment.

FIGS. 21-23 are schematic views of memory modules according to variousembodiments.

FIGS. 24-26 are schematic views of portions of memory modules accordingto various embodiments.

FIG. 27 is a schematic view of a memory module according to anotherembodiment.

FIG. 28 is a flowchart of a technique of communicating error informationaccording to an embodiment.

FIG. 29 is a flowchart of a technique of handling errors according to anembodiment.

FIG. 30 is a flowchart of a technique of handling errors according toanother embodiment.

FIG. 31A is a flowchart of a technique of communicating errorinformation according to another embodiment.

FIG. 31B is a flowchart of a technique of communicating errorinformation according to another embodiment.

FIG. 32 is a flowchart of a technique of communicating error informationaccording to another embodiment.

FIG. 33 is a flowchart of a technique of communicating error informationaccording to another embodiment.

FIG. 34 is a flowchart of a technique of communicating error informationaccording to another embodiment.

FIG. 35 is a schematic view of a system with a memory systemarchitecture according to an embodiment.

FIG. 36 is a schematic view of a server according to an embodiment.

FIG. 37 is a schematic view of a server system according to anembodiment.

FIG. 38 is a schematic view of a data center according to an embodiment.

DETAILED DESCRIPTION

The embodiments relate to memory system architectures. The followingdescription is presented to enable one of ordinary skill in the art tomake and use the embodiments and is provided in the context of a patentapplication and its requirements. Various modifications to theembodiments and the generic principles and features described hereinwill be readily apparent. The embodiments are mainly described in termsof particular methods and systems provided in particularimplementations.

However, the methods and systems will operate effectively in otherimplementations. Phrases such as “an embodiment”, “one embodiment” and“another embodiment” may refer to the same or different embodiments aswell as to multiple embodiments. The embodiments will be described withrespect to systems and/or devices having certain components. However,the systems and/or devices may include more or less components thanthose shown, and variations in the arrangement and type of thecomponents may be made without departing from the scope of thisdisclosure. The embodiments will also be described in the context ofparticular methods having certain steps. However, the method and systemoperate according to other methods having different and/or additionalsteps and steps in different orders that are not inconsistent with theembodiments. Thus, embodiments are not intended to be limited to theparticular embodiments shown, but are to be accorded the widest scopeconsistent with the principles and features described herein.

The embodiments are described in the context of particular memory systemarchitecture having certain components. One of ordinary skill in the artwill readily recognize that embodiments are consistent with the use ofmemory system architectures having other and/or additional componentsand/or other features. However, one of ordinary skill in the art willreadily recognize that the method and system are consistent with otherstructures. Methods and systems may also be described in the context ofsingle elements. However, one of ordinary skill in the art will readilyrecognize that the methods and systems are consistent with the use ofmemory system architectures having multiple elements.

It will be understood by those skilled in the art that, in general,terms used herein, and especially in the appended claims (e.g., bodiesof the appended claims) are generally intended as “open” terms (e.g.,the term “including” should be interpreted as “including but not limitedto,” the term “having” should be interpreted as “having at least,” theterm “includes” should be interpreted as “includes but is not limitedto,” etc.). It will be further understood by those within the art thatif a specific number of an introduced claim recitation is intended, suchan intent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to examples containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should be interpreted to mean “at least one”or “one or more”); the same holds true for the use of definite articlesused to introduce claim recitations. Furthermore, in those instanceswhere a convention analogous to “at least one of A, B, or C, etc.” isused, in general such a construction is intended in the sense one havingskill in the art would understand the convention (e.g., “a system havingat least one of A, B, or C” would include but not be limited to systemsthat have A alone, B alone, C alone, A and B together, A and C together,B and C together, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that virtually any disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms. For example, the phrase “A or B” will be understood toinclude the possibilities of “A” or “B” or “A and B.”

FIG. 1 is a schematic view of a system with a memory system architectureaccording to an embodiment. The system 100 includes a memory 102 coupledto a processor 104. The memory 102 is configured to store data. Whendata is read from the memory 102, the memory 102 is configured tocorrect an error, if any, in the data. For example, the memory 102 maybe configured to correct a single-bit error. The memory 102 may also beconfigured to detect a double-bit error. Although the particular numberof errors corrected has been used as an example, the memory 120 may beconfigured to correct any number of errors or detect any number oferrors. Moreover, although one or more error correction techniques mayresult in single-bit error correction and/or double-bit error detection,the memory 102 may be configured to perform any error correctiontechnique that can correct at least one error.

The memory 102 may include any device that is configured to store data.In a particular example, the memory 102 may be a dynamic random accessmemory (DRAM) module. The memory 102 may include a double data ratesynchronous dynamic random access memory (DDR SDRAM) according tovarious standards such as DDR, DDR2, DDR3, DDR4, or the like. In otherembodiments, the memory 102 may include static random access memory(SRAM), non-volatile memory, or the like.

The memory 102 is configured to generate error information in responseto correcting an error and/or attempting to correct an error in the dataread from stored data. For example, the error information may includeinformation about a corrected error, an uncorrected error, an absence ofan error, a number of such errors, or the like. Error information mayinclude the actual error, an address of the error, number of times theerror has occurred, or other information specific to the memory 102. Ina particular example, the error information may include informationabout a single-bit error indicating that the memory 102 corrected thesingle-bit error. Although particular examples of error information havebeen described, the error information may include any informationrelated to errors.

The processor 104 may be any device configured to be operatively coupledto the memory 102 and capable of executing instructions. For example,the processor 104 may be a general purpose processor, a digital signalprocessor (DSP), a graphics processing unit (GPU), an applicationspecific integrated circuit, a programmable logic device, or the like.

The processor 104 is coupled to the memory 102 through a firstcommunication path 106 and a second communication path 108. Theprocessor 104 is configured to receive data from the memory through thefirst communication path 106. For example, the first communication path106 may be a system memory interface with signal lines for data signals,strobe signals, clock signals, enable signals, or the like. That is, thecommunication path 106 may be part of a main memory channel that is theinterface between the processor 104 and the memory 102 as the mainsystem memory.

The processor 104 is also coupled to the memory 102 through a differentcommunication path, the second communication path 108. The processor 104is configured to receive the error information from the memory 102through the second communication path 108. Thus, in an embodiment, theprocessor 104 is configured to receive error information and, inparticular, corrected error information through a communication pathother than the first communication path 106. The corrected errorinformation is error information related to a corrected error. Asdescribed above, error information may include various types ofinformation related to an error. Thus, the corrected error informationmay include similar types of information related to a corrected error.

Software 110 is illustrated as coupled to the processor 104; however,the software 110 represents various programs, drivers, modules,routines, or the like the may be executed on the processor 104. Forexample, the software 110 may include drivers, kernel modules, daemons,applications, or the like. In some embodiments, the software 110 mayenable the processor 104 to be configured to perform particularfunctions described herein.

Although a single memory 102 has been used as an example, any number ofmemories 102 may be coupled to the processor 104 through twocommunication paths similar to the communication paths 106 and 108. Inan embodiment, each memory 102 may be coupled to the processor 104through a dedicated first communication path 106 separate from othermemories 102 and a dedicated second communication path 108 also separatefrom other memories 102. However, in other embodiments, the firstcommunication path 106 may be shared by more than one memory 102 and thesecond communication path 108 may be shared by more than one memory 102.Furthermore, although a single first communication path 106 has beendescribed, multiple first communication paths 106 between one or morememories 102 may be present. Similarly, although a single secondcommunication path 108 has been described, multiple second communicationpaths 108 between one or more memories 102 may be present.

In an embodiment, the communication of the error information may becommunicated through an out-of-band communication path. The secondcommunication path 108 may be such an out-of-band communication path.That is, the main communication between the processor 104 and the memory102 may be through the first communication path 106, while the errorinformation is communicated through the out-of-band second communicationpath 108.

FIG. 2 is a schematic view of a system with a memory system architectureincluding a controller according to an embodiment. In this embodiment,the system 200 includes a memory 202, a processor 204, communicationpaths 206 and 208, and software 210 similar to the memory 102, processor104, communication paths 106 and 108, and software 110 of FIG. 1.However, the second communication path 208 includes a first bus 212coupled between a controller 214 and a second bus 216 coupled betweenthe controller 214 and the processor 204. In other words, the controller214, coupled to both the processor 204 and the memory 202, is part ofthe second communication path 208.

The controller 214 may be any device configured to be operativelycoupled to the memory 202 and the processor 204. For example, thecontroller 214 may include a general purpose processor, a digital signalprocessor (DSP), an application specific integrated circuit, aprogrammable logic device, or the like.

The busses 212 and 216 may be any variety of communication links. Forexample, the buses 212 and 216 may be a system management bus (SMBus),an inter-integrated circuit (I²C) bus, an intelligent platformmanagement interface (IPMI) compliant bus, a Modbus bus, or the like. Ina particular embodiment, at least one portion of the communication path208 may be substantially slower than the communication path 206. Forexample, the communication path 206 between the memory 202 and processor204 may be designed for higher data-rate transfers on the order of 10GB/s; however, the communication path 208 may have a lower data transferrate on the order of 10 Mbit/s, 100 kbit/s, or the like. Thus, in someembodiments, a ratio of the data transfer speed of the communicationpath 206 to the communication path 208 may be about 100, 1000, or more.

In an embodiment, the second communication path 208 may be a dedicatedcommunication path. That is, the second communication path 208 may onlybe used for communication of information between the memory 202 and theprocessor 204. However, in other embodiments, the controller 214 mayallow other devices to be accessible. For example, a non-memory device268 may be coupled by the bus 212 to the controller 214. In anotherexample, other devices 266 may be coupled to the controller 214.Accordingly, information other than information from the memory 202 maybe transmitted over the bus 212 and/or the bus 216 to and from theprocessor 204 and/or memory 202. In particular, the error informationfrom the memory 202 may be communicated to the processor 204 over asecond communication path 208 that is used for other purposes, includingnon-memory purposes.

In an embodiment, the controller 214 may include non-volatile memory254. The non-volatile memory 254 may be configured to store errorinformation from the memory 202. Accordingly, error information may bemaintained in the controller 214 when power is off. The processor 204may be configured to request the error information from the controller214. Accordingly, the controller 214 may be configured to respond tosuch a request by providing the error information stored in thenon-volatile memory 254, accessing the memory 202 to retrieve the errorinformation to respond to the processor 204, or the like.

In an embodiment, the controller 214 may be configured to poll thememory 202 for error information. In another embodiment, the memory 202may be configured to push error information to the controller 214.Regardless, error information stored in the non-volatile memory 254 maybe a substantially up-to-date copy.

FIG. 3 is a schematic view of a system with a memory system architectureincluding a baseboard management controller according to an embodiment.In this embodiment, the system 300 includes a memory 302, a processor304, communication paths 306 and 308, and software 310 similar to thememory 202, processor 204, communication paths 206 and 208, and software210 of FIG. 2. However, the controller 314 is a baseboard managementcontroller (BMC) 314.

The BMC 314 may be configured to manage the system 300. For example, theBMC 314 may be coupled to various sensors of the system 300, includingsensors of the processor 304, memory 302, other devices 366, or thelike. The BMC 314 may be configured to collect and report on varioussystem parameters, such as temperature, cooling status, power status, orthe like. The BMC 314 may be configured to manage the system and enableaccess to information according to a standard. The managementinformation may be made available to the processor 304 and hence,available to the software 310. Alternatively, the BMC 314 may make theinformation available through another communication path, such as anout-of-band communication path. Here, an out-of-band communication pathmay include any communication path that does not include the processor304.

FIG. 4 is a schematic view of a system with a memory system architecturewithout processor-based error correction according to an embodiment. Inthis embodiment, the system 400 includes a memory 402, a processor 404,communication paths 406 and 408, and software 410 similar to the memory102, processor 104, communication paths 106 and 108, and software 110 ofFIG. 1. However, in this embodiment, the processor 404 includes a memorycontroller (MC) 450 and a machine check architecture (MCA) register 452.

The memory controller 450 is integrated with the processor 404. Thememory controller 450 may be part of a main memory channel that is themain interface between the processor 404 and the memory 402. The memorycontroller 450 is configured to control access to the data stored in thememory 402 through the communication path 406. In some embodiments, thememory controller 450 may be configured to correct errors, but would nothave the opportunity to correct such errors as error correction may havebeen performed by the memory 402. However, in this embodiment, thememory controller 450 is not configured to correct errors in data readfrom the memory 402. The memory controller 450 may not be configured toreport any error information based on data read from the memory 402.

The MCA register 452 is a register in which hardware errors may bereported. For example, cache errors, bus errors, data errors, or thelike may be detected and reported in the MCA register 452. However,because the memory controller 450 is not configured to correct errors indata read from the memory 402, any potential error information based onthe data read from the memory 402 may not be reported in the MCAregister 452. Regardless, as described above, the error information maybe communicated to the processor 404 through the communication path 408.Thus, the error information may still be available to the software 410,albeit not through the memory controller 450 and MCA register 452.

In an embodiment, the availability of error information through thesecond communication path 408 may allow for a lower cost system 400. Forexample, a processor 404 with the memory controller 450 without anymemory error correction may be used, yet error information may still beavailable. In particular, even if memory error correction is desired, aprocessor 404 without memory error correction may be used because theerror information is available through the second communication path408. Thus, the software 410, including any software that uses errorinformation, may still operate as if the processor 404 was capable ofmemory error correction. A processor 404 without error correction may bea lower power, lower cost processor. Thus, an overall power usage and/orcost of the system 400 may be reduced.

Although the memory controller 450 has been illustrated as beingintegrated with the processor 404, the memory controller 450 may beseparate from the processor 404. Regardless, the communication path 408may bypass the memory controller 450 and other portions of the processor404 that may otherwise have had error correction circuitry. The bypassof such components makes the communication of error information throughthe second communication path 408 substantially independent of thecharacter of the memory controller 450, MCA register 452, or the like.That is, the error information may still be available even thoughsimilar information is not available through the memory controller 450and/or the MCA register 452.

FIG. 5 is a schematic view of a system with a memory system architecturewith a poisoned data strobe signal according to an embodiment. In thisembodiment, the system 500 includes a memory 502, a processor 504,communication paths 506 and 508, and software 510 similar to the memory102, processor 104, communication paths 106 and 108, and software 110 ofFIG. 1. However, in this embodiment, the communication path 506 includesdata lines 532 and a data strobe line(s) 533. Other lines may be presentas part of the communication path 506; however, for clarity, those linesare not illustrated.

In an embodiment, error information regarding uncorrectable errors anderror information regarding correctible errors may be communicated bydifferent paths. As described above, correctible error information maybe communicated through the communication path 508. Uncorrectable errorinformation may include a variety of different types of informationbased on an uncorrectable error. Uncorrectable error information may becommunicated through the first communication path 506. For example, thememory 502 may be configured to communicate an uncorrectable error by asignal transmitted (or not transmitted) over the data strobe line(s)533. That is, during a normal data transfer, a data strobe signaltransmitted over the data strobe line(s) 533 may toggle as data istransferred; however, if the memory 502 has detected an uncorrectableerror, the memory 502 may be configured to generate a data strobe signalfor transmission over the data strobe line(s) 533 that is different froma data strobe signal during a normal data transfer. In a particularexample, the memory 502 may be configured to not toggle the data strobesignal transmitted through the data strobe line(s) 533. When such acondition is detected, the processor 504 may be configured to generate ahardware exception, which may be handled by the software 510.

Although a particular example, of a signal and/or line within thecommunication path 506 has been used as an example of a technique tocommunicate an uncorrectable error, other signals and/or lines may beused to communicate an uncorrectable error to the processor 504.Regardless of how communicated, the processor 504 may be configured torespond to such a communication of an uncorrectable error, such as byhalting the system 500 or taking another action.

FIG. 6 is a schematic view of a system with a memory system architecturewith a separate uncorrectable error signal according to an embodiment.In this embodiment, the system 600 includes a memory 602, a processor604, communication paths 606 and 608, and software 610 similar to thememory 102, processor 104, communication paths 106 and 108, and software110 of FIG. 1. However, in this embodiment, a separate communicationpath 634 is coupled between the memory 602 and the processor 604.

Similar to the system 500 of FIG. 5, an uncorrectable error may becommunicated to the processor 604. In this embodiment, the memory 602 isconfigured to communicate uncorrectable error information over the thirdcommunication path 634. For example, the third communication path 634may be a dedicated line separate from the first communication path 606.Thus, error information regarding uncorrectable errors may be receivedby the processor 604, but through a communication path other than thefirst and second communication paths 606 and 608.

FIG. 7 is a schematic view of a system with a memory system architecturewith a software module according to an embodiment. In this embodiment,the system 700 includes a memory 702, a processor 704, communicationpaths 706 and 708, and software 710 similar to the memory 102, processor104, communication paths 106 and 108, and software 110 of FIG. 1.However, in this embodiment, the software 710 includes a module 718.

The module 718 represents a part of the software 710 that is configuredto access the error information 722 through the processor. For example,the module 718 may include a kernel module, a driver, an extension, orthe like. The module 718 may include a driver for an interfaceassociated with the communication path 708. In a particular example, themodule 718 may include a driver associated with an IPMI bus, IPMI2 bus,or the like. Other information 720 may also be available to the software710. The error information 722 is illustrated separately to indicatewhat portion of the software 710 is associated with the errorinformation 722.

In an embodiment, the module 718 may cause the processor 704 to requesterror information from the memory 702. For example, the memory 702 maygenerate error information. At a later time the processor 704 maytransmit a request for the error information through the communicationpath 708. The memory 702 may be configured to respond to the requestwith the error information through the communication path 708.

FIG. 8 is a schematic view of a system with a memory system architecturewith an error detection and correction module according to anembodiment. In this embodiment, the system 800 includes a memory 802, aprocessor 804, communication paths 806 and 808, and software 810 with amodule 818 responsive to information 820 and 822 similar to the memory702, processor 704, communication paths 706 and 708, and software 710with the module 718 responsive to information 720 and 722 of FIG. 7.However, in this embodiment, the software 810 also includes an errordetection and correction (EDAC) module 824.

In an embodiment, the EDAC module may be configured to manage errorinformation from memory, caches, input/output (I/O) devices,peripherals, busses, and/or other aspects of the system 800 and may beconfigured to expose such information to a higher functional layer, suchas an application layer. In particular, the EDAC module 824 may beconfigured to receive the error information from the module 818. TheEDAC module 824 may be configured to combine the error information withother information such that other modules, applications, or the like mayhave access to the error information.

FIG. 9 is a schematic view of a system with a memory system architecturewith an aggregating module according to an embodiment. In thisembodiment, the system 900 includes a memory 902, a processor 904,communication paths 906 and 908, and software 910 with a first module918 responsive to information 920 and 922 similar to the memory 702,processor 704, communication paths 706 and 708, and software 710 withthe module 718 responsive to information 720 and 722 of FIG. 7. However,in this embodiment, the software 910 also includes a second module 926.The second module 926 is configured to receive information 920. Inparticular, this other information 920 may include information unrelatedto an error on the memory 902. At least a part 921 of the otherinformation 920 may be received by the first module 918. The firstmodule 918 may be configured to combine the error information 922 withsome or all of the other information 920 from the second module 926. Thefirst module 918 may be configured to present the combined informationwith a single interface. For example, the first module 918 may beconfigured to present the combined information to an EDAC module, suchas the EDAC module 824 of FIG. 8.

FIG. 10 is a schematic view of a system with a memory systemarchitecture with an error correction module that aggregates informationfrom a memory control architecture module according to an embodiment. Inthis embodiment, the system 1000 includes a memory 1002, a processor1004, communication paths 1006 and 1008, and software 1010 with modules1018 and 1026 responsive to information 1020 and 1022 similar to thememory 902, processor 904, communication paths 906 and 908, and software910 with the modules 918 and 926 responsive to information 920 and 922of FIG. 9. However, in this embodiment the module 1018 is an errorcorrection (EC) module 1018 and the second module 1026 is an MCA module1026.

The MCA module 1026 is configured to control access to MCA registerssuch as the MCA register 452 of FIG. 4. Information 1020 represents suchinformation from the MCA registers. The EC module 1018 is configured toaccess the MCA module 1026 to retrieve such information 1020. The ECmodule 1018 may combine the information 1020 from the MCA module 1026with the error information 1022 and present that combined informationwith a single interface.

In particular, the EC module may present an interface similar to oridentical to that of an MCA module 1026 had the processor 1004 been ableto correct errors. For example, if the processor 1004 was configured tocorrect errors in data read from the memory 1002 and such errorinformation was available, that information may be available through theMCA module 1026. However, if the processor 1004 is not configured tocorrect errors in data read from the memory 1002 or the processor 1004is configured to correct errors but never receives error information bya communication path monitored by the MCA module 1026 due to the errorsbeing corrected in the memory 1002, the MCA module 1026 would not beable to present the error information. Regardless, the EC module 1018may combine the MCA module 1026 information 1020 with error information1022 obtained through communication path 1008 and present that combinedinformation similar to or identical to information that the MCA module1026 would have provided had the processor 1004 been configured tocorrect errors in data read from the memory 1002 or the errorinformation was available to the MCA module 1026. Software may then usethe same or similar interface regardless of whether a processor 1004with error correction is present. In other words, a processor 1004capable of error correction is not necessary for software relying uponerror information to be fully operational. As a result, costs may bereduced by using a less expensive processor 1004 without errorcorrection.

FIG. 11 is a schematic view of a system with a memory systemarchitecture with multiple modules sharing an interface, according to anembodiment. In this embodiment, the system 1100 includes a memory 1102,a processor 1104, communication paths 1106 and 1108, and software 1110responsive to information 1120 and 1122 similar to the memory 702,processor 704, communication paths 706 and 708, and software 710responsive to information 720 and 722 of FIG. 7. However, in thisembodiment, the software 1110 includes a first module 1118, a secondmodule 1128 and an interface module 1130.

The first module 1118 is similar to the module 718 of FIG. 7. However,the first module 1118 is configured to receive error information fromthe memory 1102 through an interface module 1130. The interface module1130 is a module configured to provide the interface to thecommunication path 1108. For example, the interface module 1130 may be amodule configured to permit access over an IPMI bus.

Other modules, such as the second module 1128 may also be configured tocommunicate using the interface module 1130. For example, the secondmodule 1128 may be configured to access another device attached to anIPMI bus, access another aspect of the memory 1102, such as thermal orpower information, or the like. Both the error information and the otherinformation may be part of the information 1122 transferred by theinterface module 1130. In other words, the error information may betransferred using dedicated software along the entire path, but may alsoshare modules, interfaces, busses, or the like with related or unrelatedinformation and/or sources.

FIG. 12 is a schematic view of a system with a memory systemarchitecture with a correctible error module and a serial presencedetect/registering clock driver module sharing an interface according toan embodiment. In this embodiment, the system 1200 includes a memory1202, a processor 1204, communication paths 1206 and 1208, and software1210 with modules 1218, 1228, and 1230 responsive to information 1220and 1222 similar to the memory 1102, processor 1104, communication paths1106 and 1108, and software 1110 with modules 1118, 1128, and 1130responsive to information 1120 and 1122 of FIG. 11. However, in thisembodiment, the first module 1218 is a corrected error (CE) module 1218and the second module 1228 is a serial presence detect (SPD)/registeringclock driver (RCD) module 1228.

In particular, the SPD/RCD module 1228 is configured to accessinformation related to a serial presence detect system and/or aregistering clock driver system. The SPD/RCD module 1228 may beconfigured to access one or both of such systems. The information isaccessed through the second communication path 1208. Thus, in anembodiment, the error information from the memory 1202 may be accessedthrough the same communication path 1208 as SPD/RCD related information.

FIG. 13 is a schematic view of a system with a memory systemarchitecture with in-DRAM error correction according to an embodiment.In this embodiment, the system 1300 includes memories 1302, a processor1304, kernel 1310 with an EC module 1318 and an MCA module 1326responsive to information 1320 and 1322 similar to the memory 1002,processor 1004, and software 1010 with the EC module 1018 and MCA module1026 responsive to information 1020 and 1022 of FIG. 10. However, inthis embodiment, each of the memories 1302 is error correction code(ECC) dual in-line memory module (DIMM). Each ECC DIMM 1302 isconfigured to store data and correct at least an error in the storeddata. In this embodiment, the ECC DIMMs 1302 are each coupled to amemory controller (MC) 1350 of the processor 1304 through correspondingcommunication paths 1364. The communication paths 1364 include at leastlines for data signals and data strobe signals or the like similar tothe communication path 506 of FIG. 5. The ECC DIMMs 1302 are eachcoupled to the processor 1304 through a communication path 1308including a bus 1312, a BMC 1314, and a bus 1316 similar to the bus 312,BMC 314, and bus 316 of FIG. 3.

In an embodiment, the ECC DIMMs 1302 may be configured to correct one ormore errors in data read from the ECC DIMMs 1302. The error correctiontechniques may include a single error correction—double error detection(SEC-DEC) technique, a single-chip chipkill technique, a double-chipchipkill technique, or the like. Any error correction technique may beused.

In this embodiment, the memory controller (MC) 1350 is not configured toperform error correction or alternatively, is not configured to receiveerror information from the ECC DIMMs 1302. As the data passed from theECC DIMMs 1302 is already corrected, the MC 1350 may not even receiveany information representing a correctible error. However, the errorinformation and, in particular, corrected error information may betransmitted to the processor 1304 through the communication path 1308,i.e., through the busses 1312 and 1316, and the BMC 1314.

In an embodiment, the processor 1304 may be an existing processor thatis otherwise not capable of performing error correction, but has aninterface capable of connecting to the bus 1316. However, once theprocessor 1304 is configured by the kernel 1310 and, in particular, theEC module 1318, the overall system 1300 may be configured to performerror correction similar to a system having a processor capable of errorcorrection.

In an embodiment, the EC module 1318 may create a virtual memorycontroller with ECC interface. For example, as described above, the ECmodule 1318 may be configured to receive information from the MCA module1326. That information may be the information that an actual memorycontroller with ECC interface may provide without some or all errorinformation. The EC module 1318 may supplement the information from theMCA module 1326 with the error information to create a complete set ofinformation expected from a memory controller with ECC interface. As aresult, the EDAC module 1324, a memory ECC daemon 1358, otherapplications 1360, or the like may be used without change from thoseused with processors with error correction. For example, the EDAC module1324 may be configured to poll the EC module 1318 for memory ECCinformation. In return, the EC module 1318 may return the errorinformation received through the second communication path 1308. Thememory ECC daemon 1358, in communication with the EDAC module 1324, maypoll the EDAC module 1324 for error information. The memory ECC daemon1358 may then take actions according to the error information at anapplication level. Such actions may include page retirement, otheractions to manage errors to keep the system 1300 running, maintain alevel of reliability, recommend decommissioning, or the like.

As described above, an uncorrectable error may be detected. Theuncorrectable error information may be communicated through the MC 1350,MCA register 1352, and MCA module 1326 to the EC module 1318. Forexample, an uncorrectable error may be communicated by a non-maskableinterrupt, exception, or the like through the MCA module 1326. In aparticular example, the memory controller 1350 may generate a hardwareexception in response to an uncorrectable error, regardless of howcommunicated to the memory controller 1350. The MCA module 1326 mayintercept that exception and pass it to the EC module 1318. The ECmodule 1318 may then communicate the exception to the EDAC module 1324.In addition to or instead of communicating uncorrectable errorinformation as described above, uncorrectable error information may becommunicated through the communication path 1308.

In an embodiment, the ECC DIMMs 1302 may be configured to providecorrected data to the processor 1304. However, the data may becomecorrupted between the ECC DIMMs 1302 and the MC 1350. Accordingly, someform of error correction may be performed between the ECC DIMMs 1302 andthe processor 1304 or MC 1350. For example, the data transmitted fromthe ECC DIMMs 1302 may be encoded with error correction codes intendedto detect errors that occur over the communication link 1364. With sucherror correction, substantially the entire path from storage element inthe ECC DIMMs 1302 to the processor may be protected with errorcorrection.

FIGS. 14A-D are schematic views of systems with a memory systemarchitecture with in-module error correction according to someembodiments. Referring to FIG. 14A, the system 1400 includes componentssimilar to those of FIG. 13; however, in this embodiment, the ECC DIMMs1402 include a buffer 1462. The buffer 1462 is configured to correcterrors in data read from the corresponding ECC DIMM 1402. In particular,uncorrected data may be read from internal memory devices, such as DRAMdevices (not illustrated) of the ECC DIMM 1402. The buffer 1462 may beconfigured to correct the uncorrected data and generate corrected errorinformation similar to other memories described herein. That errorinformation may be communicated through the communication path 1408, andmay be used as described above. That is, the error information may beused as described above regardless of how the error information isgenerated.

Referring to FIG. 14B, the components of the system 1400 may be similarto those of FIG. 14A. However, in this embodiment, the EDAC module 1424is configured to communicate with the MCA module 1426. For example, theEDAC module 1424 may be configured to poll the MCA module 1426 forhardware related information, uncorrectable error information, or otherinformation available through the MCA module 1426 as described above.The EDAC module 1424 may be configured to combine the information fromthe MCA module 1426 with information from the EC module 1418.

Referring to FIG. 14C, the components of the system 1400 may be similarto those similar to those of FIG. 14A. However, in this embodiment, anMCELOG module 1425 is configured to receive information from the CEmodule 1418. The MCELOG module 1425 may be configured to record machinecheck events (MCEs) related to various system errors, such as memoryerrors, data transfer errors, or other errors. The MCELOG module 1425may be configured to raise an interrupt to the Memory ECC Daemon 1458and pass error information to the Memory ECC Daemon 1458.

Referring to FIG. 14D, the components of the system 1400 may be similarto those of FIG. 14C. However, in this embodiment, similar to thedifference between FIGS. 14A and 14B, the MCELOG module 1425 may beconfigured to receive information from the MCA module 1426 similar tothe EDAC module 1424 of FIG. 14B.

Although different modules have been described with respect to ECC DIMMs1402 with buffers 1462 in FIGS. 14A-D, in other embodiments, the variousconfigurations may be applied to the system 1300 of FIG. 13 with ECCDIMMs 1302.

FIG. 15 is a schematic view of a memory module according to anembodiment. The memory module 1500 includes one or more memory devices1501, a data interface 1536, an error interface 1538, and a controller1541. The data interface 1536 is configured to transmit and receive data1540 from data stored in the memory devices 1501. The memory module 1500is configured to generate error information for data read from the oneor more memory devices 1501. The error interface 1538 is configured totransmit error information generated in response to correcting an errorin data read from the one or more memory devices 1501.

The data interface 1536 is the interface through which data stored inthe memory devices 1501 is transmitted and the interface through whichdata 1540 to be stored in the memory devices 1501 is received. Forexample, the data interface 1536 may include buffers, drive circuits,terminations, or other circuits for lines such as data lines, strobelines, address lines, enable lines, clock lines, or the like

The error interface 1538 may be an interface configured to communicateover a particular bus, such as SMBus, IPMI, or other buses as describedherein. In an embodiment, the error interface 1538 may be an existinginterface through which the memory module 1500 communicates otherinformation in addition to the error information. Thus, the information1542 would include not only the error information, but also the otherinformation.

The controller 1541 may be any device configured to be operativelycoupled to the memory devices 1501. For example, the controller 214 mayinclude a general purpose processor, a digital signal processor (DSP),an application specific integrated circuit, a programmable logic device,or the like. As will be described in further detail below, thecontroller 1541 may include a buffer, such as an RCD, or the like.

The controller 1541 is coupled to the memory devices 1501, the datainterface 1536, and the error interface 1538. The controller 1541 isconfigured to obtain the error information. In an embodiment, thecontroller 1541 may obtain the error information from the memory devices1501; however, in other embodiments, the controller 1541 may beconfigured to correct errors in data from the memory devices 1501 andgenerate the error information.

In an embodiment the controller 1541 may be configured to communicate anuncorrectable error through the data interface 1536. For example, asdescribed above, a data strobe signal may be used to indicate anuncorrectable error. The controller 1541 may be configured to modify thedata strobe signal transmitted through the data interface 1536 inresponse to detecting an uncorrectable error.

FIG. 16 is a schematic view of a memory module with an SPD or RCDinterface according to an embodiment. In this embodiment, the memorymodule 1600 includes one or more memory devices 1601, a data interface1636, an error interface 1638, and a controller 1641 similar to the oneor more memory devices 1501, data interface 1536, error interface 1538,and controller 1541 of FIG. 15. However, the error interface 1538 ofFIG. 15 is an SPD/RCD interface 1638 here.

The SPD/RCD interface 1638 may be used to provide access to an SPDsystem or an RCD system (not illustrated). In a particular embodiment,the error information may be available through a particular register ormemory location within such an SPD or RCD system. Thus, the errorinformation may be obtained through the same interface the SPD or RCDinformation may be obtained.

As the error information is available through an existing hardwareinterface, additional hardware may not be needed. For example, a commandreceived through the SPD/RCD interface 1638 intended to access errorinformation may be different from other commands by an address, registeraddress, or other field unused by SPD/RCD systems. In an embodiment, anew register for SPD/RCD systems may be defined that exposes the errorinformation. In another embodiment, an existing register may be reusedto communicate the error information.

FIG. 17 is a schematic view of a memory module with a separateuncorrectable error interface according to an embodiment. In thisembodiment, the memory module 1700 includes one or more memory devices1701, a data interface 1736, an error interface 1738, and a controller1741 similar to the one or more memory devices 1501, the data interface1536, the error interface 1538, and the controller 1541 of FIG. 15.However, the memory module 1700 also includes an uncorrectable error(UE) interface 1744.

The UE interface 1744 is a separate interface through which the memorymodule 1700 is configured to communicate uncorrectable errors. Forexample, the UE interface 1744 may be a dedicated line, a dedicated bus,or the like.

FIG. 18 is a schematic view of a memory device according to anembodiment. In this embodiment, the memory device 1800 includes a datainterface 1836 and an error interface 1838. The data interface 1836 andthe error interface 1838 may be similar to the data interface 1536 andthe error interface 1538 of FIG. 15, or the like as described above;however, in this embodiment, the data interface 1836 and the errorinterface 1838 are interfaces to the memory device 1800 rather than amemory module, such a memory module 1500 of FIG. 15.

The memory device 1800 includes a controller 1841. The controller 1814may be any device configured to be operatively coupled to the memory1801 and the interfaces 1836 and 1838. For example, the controller 1841may include a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit, a programmable logicdevice, or the like

The memory 1801 is configured to store data. For example, the memory1801 may be a memory cell array; however, in other embodiments, the datamay be stored in other configurations. The memory 1801 may includeelectrical, magnetic, chemical, optical, or other types of storageelements.

The controller 1841 is configured to transmit data stored in the memory1801 through the data interface 1836. The controller may also beconfigured to receive data to be stored in the memory 1801 through thedata interface 1836. Such transfers are represented by data 1840.

The controller 1841 is configured to transmit error informationgenerated in response to correcting an error in data read from memory1801 through the error interface 1838. The error information may besimilar to any of the types of error information described above. Thecontroller 1841 may also be configured to receive commands,instructions, or other information through the error interface 1838.Such transfers of error information, commands, instructions, or otherinformation is represented by information 1842.

In this embodiment, both the data 1840 and information 1842 areillustrated as passing through the controller 1841. However, in otherembodiments, components of the memory device 1800 may be controlled bythe controller 1841 such that data 1840 and information 1842 does notpass through the controller 1841. For example, in some embodiments, thedata and/or error information may be provided to the data interface 1836and error interface 1838 under control of the controller 1841, butbypassing the controller 1841.

FIG. 19 is a schematic view of a memory device according to anotherembodiment. In this embodiment, the memory device 1900 includes a memorycell array 1901. The memory cell array 1901 may include memory cells inwhich data is stored. In particular, the memory cell array 1901 may beconfigured to store encoded data. Sense amplifiers 1902 and writecircuitry 1904 are examples of circuitry in the memory device 1900 thatallows data to be written to and read from the memory cell array 1901 toan address or addresses specified by the address 1906. However, in otherembodiments, other read and write circuitry may be associated with thememory cell array 1901. Furthermore, although the sense amplifiers 1902and write circuitry 1904 are illustrated as part of the memory cellarray 1901, such circuitry may be separate from the memory cell array1901. In addition, although a single memory cell array 1901 isillustrated, multiple memory cell arrays 1901 may be present.

The memory cell array 1901 is coupled to an error correcting code (ECC)engine 1908. The ECC engine 1908 is configured to correct at least oneerror in data read from the memory by encoding data written to thememory cell array 1901 and decoding data read from the memory cell array1901. In particular, the ECC engine 1908 may be configured to receivewrite data 1910. The ECC engine 1908 may be configured to encode thewrite data 1910 such that the encoded data may be written to the memorycell array 1901 by the write circuitry 1904 to a location specified bythe address 1906. Similarly, the ECC engine 1908 may be configured toreceive encoded data read from the memory cell array 1901 and decodethat data into decoded output data 1924. Such encoding and decoding maybe performed according to any number of ECC algorithms as describedherein. As an example, Single Error Correct—Double Error Detect(SEC-DED) may be used as the ECC algorithm; however others may be used.

Although signals such as an address 1906 and write data 1910 areillustrated as signals used in writing data to the memory cell array1901, the memory device 1900 may be configured to receive and processother signals involved in writing data to the memory cell array 1901;however, such components are omitted for clarity. Furthermore, othercomponents that may modify an address 1906, redirect an access, or thelike may be present, but are also not illustrated for clarity.

In a particular example, during a write operation, the ECC Engine 1908is configured to receive the bits the memory device 1900 should store asthe write data 1910. The ECC Engine 1908 is configured to calculate theECC bit value(s) for the write data 1910 and pass these ECC bit(s),along with the original data values as the encoded data, to the memorycell array 1901 using the write circuitry 1904. The memory cell array1901 is then configured to store the encoded data.

During a read operation, the ECC Engine 1908 is configured to receiveencoded data from the memory cell array 1901. That is, the senseamplifiers 1902 and other circuitry are used to read the previouslystored ECC bit(s) and original data values as the encoded data. The ECCengine 1908 may then decode the encoded data, generate output data 1924,and generate any error information.

The output data 1924 may then be output from the memory device 1900. Insome embodiments, other components may be disposed between the ECCengine 1908 and the output of the memory device 1900. In an embodiment,a buffer 1932 may be configured to buffer the output data 1924. Inanother embodiment, an RCD module 1934 may be configured to receive,buffer, and output the output data 1924. Here, examples of such optionalcomponents are illustrated with dashed lines.

The ECC engine 1908 is also configured to generate error flags. Forexample, the ECC engine 1908 may be configured to generate a correctableerror (CE) flag. The CE flag may be set when the ECC engine 1908successfully corrects an n-bit error, where n is less than or equal to anumber of bit-errors that the ECC engine 1908 is configured to correct.The ECC engine 1908 may also be configured to generate an uncorrectableerror (UE) flag. The UE flag may be set when the ECC engine 1908 detectsthat a number of bit-errors have occurred greater than a number ofbit-errors that the ECC engine 1908 is configured to correct. In aparticular example, with SEC-DED, the CE flag may indicate that asingle-bit error has been corrected while the UE flag may indicate thata two-bit error has occurred.

The ECC controller 1918 is configured to manage the error correction andassociated error information. The ECC controller 1918 is configured toreceive error information 1914 from the ECC engine. The errorinformation 1914 may include information indicating whether there was noerror, a correctable error, an uncorrectable error, a number of errors,or the like. The ECC controller 1918 may also be configured to receivethe address 1906 associated with a read. Accordingly, the ECC controller1918 may combine the error information 1914 from the ECC engine 1908into new error information with the address 1906. As will be describedin further detail below, the ECC controller 1918 may be configured togenerate write data 1910 to be encoded by the ECC engine 1908 andwritten to the memory cell array 1901.

In an embodiment, the ECC controller 1918 may include a memoryconfigured to store error information. For example, the ECC controller1918 may include multiple registers in which error information may bestored. Any variety of error information may be stored in the ECCcontroller 1918. As will be described in further detail below, recordsof the error may be stored including information about an error. Forexample, the error record may include information such as addressinformation, type of error, the data read from the memory cell array1901, whether a repair or other action has been performed, or the like.

In an embodiment, the ECC controller 1918 may be configured to transmitand receive communications 1926 from external devices. For example, thecommunications 1926 may include the transmission of error information.When a correctable error or an uncorrectable error occurs, errorinformation may be transmitted by the ECC controller 1918. Suchtransmission may be in response to a request from an external device ormay be spontaneous, such as according to a regular schedule, on theoccurrence of the error, during a refresh cycle, or the like.

In an embodiment, the ECC controller 1918 may be configured tocommunicate over a bus, such as the SMBus to communicate the errorinformation. In some embodiments, the memory device 1900 may include acommand buffer 1928. The command buffer 1928 may be configured to buffercommands received through a bus for the ECC controller 1918.

In an embodiment, the memory device 1900 may include an SPD module 1930.The ECC controller 1918 may be configured to communicate with the SPDmodule 1930. The SPD module 1930 may be configured to perform operationsassociated with an SPD interface. In addition, the SPD module 1930 maybe configured to allow access to the error information available throughthe ECC controller 1918. For example, particular commands receivedthrough at SPD module 1930 may be translated into appropriate commandsand/or signals to access the error information stored in the ECCcontroller 1918.

DQS modifier 1920 is configured to modify a data strobe signal 1912 fromthe memory cell array 1901 in response to error information 1916 fromthe ECC engine 1908 and output the modified data strobe signal 1922. Ina particular embodiment, the error information 1916 is a signalindicating whether an uncorrectable error has occurred. The DQS modifier1920 may be configured to modify the data strobe signal 1912 such thatthe output data strobe signal 1922 does not toggle if the errorinformation 1916 indicates that an uncorrectable error has occurred, butpasses the data strobe signals 1912 as is if an uncorrectable errorsignal has not occurred. For example, the DQS modifier 1920 may includelogic circuitry such as an OR gate, an AND gate, a NAND gate, atransmission gate or the like.

In an embodiment, the DQS modifier 1920 may be used to communicatetime-sensitive information. For example, when an uncorrectable error hasoccurred, that error may be associated with a current read operation.While information regarding the uncorrectable error may be communicatedby the ECC controller 1918 to external devices, such as by an SMBus, thecommunication path may be slower than a communication path for the data1924. Thus, communication of the occurrence of the uncorrectable errormay be delayed relative to the corresponding read operation. Incontrast, communicating that an uncorrectable error has occurred by theDQS modifier 1920 may be substantially contemporaneous with thecorresponding read operation. That is, the modified output data strobesignal 1922 is the data strobe signal associated with the transfer ofdata 1924 with the uncorrectable error.

Although particular components of a memory device 1900 have been used asan example, other components may be present. For example, the memorydevice 1900 may be configured to receive and/or transmit various strobesignals, selection signals, control signals, enable signals, or thelike.

FIG. 20 is a schematic view of a memory module including memory devicesaccording to an embodiment. In this embodiment, the memory module 2000includes a data interface 2036 and an error interface 2038 similar todata interface 1536 and error interface 1538 of FIG. 15. However, inthis embodiment, the memory module 2000 includes multiple ECC memorydevices 2001-1 to 2001-N. The ECC memory devices 2001 may be any of thememory devices described herein, such as the memory devices 1800 and1900 of FIGS. 18 and 19 described above.

Using memory device 1800 as an example of the memory devices 2001 andreferring to FIGS. 18 and 20, each of the memory devices 1800 is coupledto the data interface 2036 and the error interface 2038. With respect tothe data interface 2036, the data interfaces 1836 of the memory devices1800 may form at least part of the data interface 2036. For example,data I/Os, strobe signals, or the like of each data interface 1836 maybe aggregated into the data interface 2036. Address inputs and/or othercontrol signals of the data interface 2036 may be distributed to thedata interfaces 1836 of the memory devices 1800. Accordingly, data maybe communicated to and from the memory devices 1800 through the datainterface 2036 and hence, to and from the memory module 2000.

Similarly, the error interfaces 1838 may be coupled to the errorinterface 2038. The error interfaces 1838 may be coupled in a variety ofways. For example, the error interfaces 1838 and the error interface2038 may be coupled to a common bus within the memory module 2000. Inanother example, the error interface 2038 may be coupled directly toeach error interface 1838 of the memory devices 2001. The errorinterface 2038 may be configured to aggregate the error information fromthe memory devices 1800. Accordingly, error information may becommunicated from the memory devices 1800 through the error interface2038 and hence, from the memory module 2000.

Although the memory device 1800 of FIG. 18 has been used as an exampleof a memory device 2001 of the memory module 2000, in other embodiments,different memory devices may be used. For example, the memory device1900 of FIG. 19 may be used as the memory devices 2001. Referring toFIG. 19, the address 1906, write data 1910, output data 1924, datastrobe signal 1922, or the like of each memory device 1900 may becoupled to the data interface 2036. Similarly, the ECC controller 1918of each memory device 1900 may be coupled to the error interface 2038.

FIGS. 21-23 are schematic views of memory modules according to variousembodiments. Referring to FIG. 21, in this embodiment, the memory module2100 includes one or more memory devices 2101, a data interface 2136,and a controller 2141 similar to the one or more memory devices 1501,data interface 1536, and controller 1541 of FIG. 15. A module errorinterface 2138 may be similar to the error interface 1538 and configuredto exchange information 2142 similar to information 1542; however themodule error interface 2138 is referred to with the term “module” todistinguish it from the device error interfaces 2139 of the memorydevices 2101. As will be described in further detail below, the moduleerror interface 2138 may be used for communication other thancommunicating error information.

Here, the memory devices 2101 each have a data interface 2137 and adevice error interface 2139 similar to data interface 1836 and errorinterface 1838 of FIG. 18. The data interfaces 2137 of the memorydevices 2101 are coupled to the data interface 2136 of the module;however, such coupling is not illustrated for clarity. Moreover, in someembodiments, the coupling of the data interface 2136 and the datainterfaces 2137 of the memory devices 2101 may, but need not passthrough the controller 2141. For example, in some embodiments, data 2140transferred to and from the memory module 2100 may be buffered in thecontroller 2141; however, in other embodiments, such transfers maybypass the controller 2141.

Each memory device 2101 is coupled to the module error interface 2138and configured to communicate error information through the device errorinterface and the module error interface. In this embodiment, acontroller 2141 is coupled to the device error interfaces 2139 and themodule error interface 2138.

As will be described in further detail, the controller 2141 may beconfigured to manage communications involving the memory devices 2101such as communications involving error information. For example, thecontroller 2141 may be configured to manage access to error informationassociated with the memory devices 2101 through the corresponding deviceerror interfaces 2139, forward communications to and from the memorydevices 2101, aggregate error information from the memory devices 2101,or the like.

In a particular embodiment, the controller 2141 may include registers2149 that are accessible through the module error interface 2138. Thecontroller 2141 may be configured to collect error information from thememory devices 2101 by communicating with the memory devices 2101through the device error interfaces 2139. Such error information may bestored in the registers 2149 and accessible to devices external to thememory module 2100. Alternatively, the controller 2141 may be configuredto combine the error information, summarize the error information, orthe like. In particular, in an embodiment, each memory device 2101 maygenerate its own error information in isolation from the other memorydevices 2101. Accordingly, as the controller 2141 may have access to allof the memory devices 2101, the controller 2141 may be configured togenerate additional error information that an individual memory device2101 may not be capable of generating. Although registers 2149 have beenused as an example, error information and other information may bestored in the controller 2141 in other ways.

In an embodiment, the controller 2141 may be configured to receivecommands related to the memory devices 2101. As described herein, thecontroller 2141 may be configured to receive a command to read errorinformation. However, the controller 2141 may be configured to receiveother types of communications related to the memory devices 2101. Forexample, the controller 2141 may be configured to receive commandsrelated to maintenance of the memory devices 2101. An example of suchmaintenance may be a command to repair a memory cell within one or moreof the memory device 2101, rewrite data, initiate a refresh cycle, orthe like. The controller 2141 may be configured to receive suchcommunications and, in response, communicate with the memory devices2101.

Referring to FIG. 22, in this embodiment, the memory module 2200 issimilar to the memory module 2100; however, the memory module 2200includes a serial presence detect (SPD) 2143 module coupled to thecontroller 2141. The SPD 2143 may be configured to communicate throughthe controller 2141. For example, the controller 2141 may be configuredto forward communications to and from the SPD 2143. In otherembodiments, the controller 2141 may be configured to obtain informationfrom the SPD 2143 and operate as a proxy for the SPD 2143 using suchinformation through the module error interface 2138. Again, although themodule error interface 2138 uses the term “error,” information otherthan error information may be transmitted and received through themodule error interface 2138.

In an embodiment, the controller 2141 may be configured to respond to anaddress associated with the SPD 2143. However, the controller 2141 maybe configured to respond to another address, use additional informationin a communication, or the like to determine whether the communicationis intended for the SPD 2143, intended to access error information,intended for the memory devices 2101, intended for the controller 2141itself, or the like.

Referring to FIG. 23, in this embodiment, the memory module 2300 may besimilar to the memory module 2100 of FIG. 21 or the memory module 2200of FIG. 22. However, a registering clock driver (RCD) module 2145 may beused in place of the controller 2141. Here, the RCD 2145 may beconfigured to buffer data transferred to and from the memory module2300. In addition, the RCD 2145 may also be configured to providefunctions described herein with respect to the controller 2141.

An SPD 2143 may also be coupled to the RCD 2145. Accordingly, similar tothe memory module 2200, the SPD 2143 may be accessible through the RCD2145, the RCD 2145 may act as a proxy for the SPD 2143, or the like,similar to the controller 2141 described above.

FIGS. 24-26 are schematic views of portions of memory modules accordingto various embodiments. Referring to FIG. 24, in this embodiment, thecontroller 2141, memory devices 2101, and the SPD 2143 may be similar tothose of FIG. 22. The controller 2141 may be coupled to a bus 2452. Thebus 2542 may be an SMBus, or other bus as described herein. The bus 2542may form part or all of the module error interface 2142.

The controller 2141 may be configured to receive an address 2454. Theaddress 2454 may be a hardwired input. In a particular example, theaddress 2454 may be a series of pins on a memory module that, wheninserted in a particular socket, are connected to high or low values todistinguish the memory module from others coupled to the same bus 2542.

In an embodiment, the address 2454 may be the address that is coupled toan SPD module in conventional memory devices; however, here, the addressis repurposed to communicate with the controller 2141 instead of an SPDsuch as the SPD 2143. Thus, a memory module as described herein may bepin-compatible with existing memory modules.

In this embodiment, the SPD 2143 and the memory devices 2101 are eachcoupled to the controller 2141 through separate busses 2450. Here, thebusses are labeled bus 2450-1 to 2450-N, corresponding to memory devices2101-1 to 2101-N. Bus 2450-N+1 corresponds to the additional buscoupling the controller 2141 and the SPD 2143. In a particularembodiment, each of the busses 2450 may be SMBus busses or other similarcommunication links. However, in other embodiments other point-to-pointcommunication links may be used in place of the busses 2450 including,for example, a communication link that may only have two endpoints. Thatis, although the term bus has been used, the communication link may beconfigured to only be able to couple to two devices.

In an embodiment, the SPD 2143 may be configured to respond to and/orgenerate a control signal 2147. The control signal 2147 may include anout-of band signal with respect to the bus 2450-N+1. The control signal2147 may be an interrupt signal, for example. In a particular,embodiment, the control signal 2147 may be an event signal associatedwith the SPD 2143. The controller 2141 may also be configured to receiveand/or generate a control signal 2451. The control signal 2451 may be asignal that would otherwise be used by the SPD 2143. However, since thecontroller 2141 may be configured to use the interface that the SPD 2143otherwise would have, the SPD 2143 may not be configured to directlyreceive the control signal 2451. Accordingly, the controller 2141 may beconfigured to communicate the control signal 2451 to and/or from the SPD2143 as the control signal 2147. Although a single control signalassociated with the SPD has been used as an example, in otherembodiments, multiple control signals may be forwarded to and from theSPD 2143, the memory devices 2101, or other components. For clarity suchcontrol signals will not be illustrated in subsequent figures; however,they may be present.

Moreover, the controller 2141 may include additional functions beyondthe SPD 2143 that may be associated with a control signal similar tocontrol signal 2147. For example, the controller 2141 may be configuredto generate an interrupt based on error information from the memorydevices 2101. Accordingly, control signal 2451 may be used tocommunicate the error information based interrupt in addition to anysuch signal from the SPD 2143. The controller 2141 may be configured todetermine whether such control signal is intended for the controller2141, the SPD 2143, or the like.

In an embodiment, a number of additional pins may be used for the memorydevices 2101. In a particular embodiment, a memory device 2101 mayinclude two additional pins, one for a clock signal and another for adata signal. The controller 2141 may include 2×(N+2) pins for the busses2452 and 2450-1 to 2450-N+1, three pins for the address 2454, and twopins for the control signals 2451 and 2147.

Referring to FIG. 25A, in this embodiment, the controller 2141, memorydevices 2101, and the SPD 2143 may be similar to those of FIG. 24.However, the controller 2141 is coupled to the memory devices 2101through bus 2450-1 and coupled to the SPD 2143 through bus 2450-2. Inthis embodiment, the busses 2450-1 and 2450-2 are separate busses.

In addition, the bus 2450-1 is a common bus for the memory devices 2101.Once again, the busses 2450 may be SMBus busses. Since multiple memorydevices 2101 may be coupled to the bus 2450-1, each memory device 2101may include a corresponding ID input 2456. The ID 2456 may be similar tothe address 2454. For example, for each memory device 2101, thecorresponding ID 2456 may be hardwired to an address unique among thememory devices 2101. In a particular example, each ID 2456 may includefour pins that may be held either high or low. Accordingly, 16 uniqueaddresses are available for the IDs 2456. Although four pins have beenused as an example, any number of pins may be used to distinguish anynumber of memory devices 2101.

Each of the memory devices 2101 may be configured to transform thecorresponding ID 2456 into an address or other identifier to be used onthe bus 2450-1. In an embodiment, the address generated from the ID 2456may be an address used as the slave address for an SMBus. In thisembodiment, the SPD 2143 and the controller 2141 may be the only deviceson the bus 2450-2. Accordingly, an address input need not be used forthe SPD 2143.

In an embodiment, a number of additional pins may be used for the memorydevices 2101. In a particular embodiment, a memory device 2101 mayinclude two additional pins, one for a clock signal and another for adata signal, similar to FIG. 24, but also four pins for the IDs 2456.The controller 2141 may include six pins for the busses 2452, 2450-1,and 2450-2, three pins for the address 2454, and two pins for thecontrol signals 2451 and 2147 similar to FIG. 24, if used.

Referring to FIG. 25B, in this embodiment, the controller 2141, memorydevices 2101, and the SPD 2143 may be similar to those of FIG. 25A.However, the SPD 2143 and the memory devices 2101 are coupled to thecontroller 2141 through a common bus 2450. As described above, thememory devices 2101 may each be configured to receive an ID 2456. Sincethe SPD 2143 is now on the same bus 2450 as the memory devices 2101, theSPD 2143 may be configured to use an address that is unique among theSPD 2143 and the memory devices 2101. The SPD 2143 may be configured toreceive an ID 2457. The SPD 2143 may be configured to convert the ID2457 into an address to use on the bus 2450.

In an embodiment, the form of the ID 2457 may be different from the IDs2456. For example, the ID 2457 may include three pins used to indicatethe address of the SPD 243 while the IDs 2456 may each include fourpins. Moreover, IDs on the ID 2457 and the IDs 2456 may, but need notcorrespond to the same address. For example, an ID 2457 of 010b and anID 2456 of 0010b may correspond to different addresses.

In an embodiment, a number of additional pins may be used for the memorydevices 2101. In a particular embodiment, a memory device 2101 mayinclude two additional pins, one for a clock signal and another for adata signal, similar to FIG. 24, but also four pins for the IDs 2456.The controller 2141 may include four pins for the busses 2450 and 2452,three pins for the address 2454, and two pins for the control signals2451 and 2147 similar to FIG. 24, if used.

Referring to FIG. 26, in this embodiment, the controller 2141, memorydevices 2101, and the SPD 2143 may be similar to those of FIG. 25B. TheSPD 2143 is configured to receive the address 2454 similar to thecontroller 2141. However, in this embodiment, the memory devices 2101are not configured to receive IDs 2456. In contrast, the memory devices2101 are each coupled to a common bus 2459, such as a single wire or netseparate from the bus 2450-1. In an embodiment, the common bus 2459 maybe a daisy-chain link.

In an embodiment, the memory devices 2101 may be coupled to a bus 2459.The memory devices 2101 are configured to determine if informationreceived through the controller 2141 is associated with the memorydevice 2101 in response to a signal received through the bus 2459. In anembodiment, the memory devices 2101 may be configured to communicateover the bus 2459 to establish the addresses of the memory devices 101on the bus 2450. For example, a first memory device may determine itsaddress in response to a counter and increment the counter. The value ofthe counter is transmitted to a second memory device 2101. The secondmemory device 2101 is also configured to determine its address inresponse to the counter and increment the counter. This procedure maycontinue until each memory device 2101 has a unique address.

In an embodiment, a number of additional pins may be used for the memorydevices 2101. In a particular embodiment, a memory device 2101 mayinclude two additional pins, one for a clock signal and another for adata signal, similar to FIG. 24, but also one additional pin for the bus2459. The controller 2141 may include six pins for the busses 2452,2450-1, and 2450-2, three pins for the address 2454, and two pins forthe control signals 2451 and 2147 similar to FIG. 24, if used.

In an embodiment, in any of the above configurations, the controller2141 may be configured to determine the addresses of the memory devices2101 and the SPD 2143, if coupled to the same bus. For example, thecontroller 2141 may be configured to use the SMBus address resolutionprotocol to dynamically assign addresses to the memory devices 2101 andthe SPD 2143. Although one technique of determining the addresses on onetype of bus has been used as an example, other techniques may be used asappropriate to the particular bus 2450.

FIG. 27 is a schematic view of a memory module according to anotherembodiment. In this embodiment, the memory module 2700 is similar to thememory module 2100 of FIG. 21. However, a repeater 2750 is used as thecontroller 2141. The repeater 2750 may be configured to extend thecommunication link coupled to the module error interface 2138 so thatthe error interfaces 2139 of the memory devices 2101 and an SPD 2143, ifpresent, may be coupled to the communication link. In a first example,if the loading of the memory devices 2101 and/or attributes of thenetwork allow, the repeater 2750 may merely be wires, such as wires of ashared medium. In another example, the repeater 2750 may include adevice configured to allow more devices to be attached to the bus, allowa longer bus, or the like. Although the term repeater has been used, therepeater 2750 may also include a hub, extender, switch, bridge, or thelike. And device that can extend a network may be used as the repeater2750. As the memory devices 2101 may be directly accessible through themodule interface 2138, each memory device 2101 of a memory module 2700may be individually interrogated for error information by an externalcontroller as described above, such as a BMC.

In an embodiment, a configuration of the memory devices 2101, an SPD2143 and the repeater 2750 may be similar to that of FIG. 25B. That is,referring to FIGS. 25B and 27, the memory devices 2101 may be eachcoupled to the bus 2450, which is also coupled to the repeater 2750.Each of the memory devices 2101 may also be configured to receive an ID2456. As a result, the memory devices 2101 may be configured todetermine their respective addresses for use on the bus 2450.

In an embodiment, particular addresses or IDs may be associated withvarious types of devices. For example, temperature sensors may beassociated with a particular address or address range. However, thememory devices 2101 may not have such an address or ID association.Accordingly, an address, ID, range of such parameters, or the like maybe repurposed from other types of devices, such as devices that are notused in a system that may use the memory modules described herein. Forexample, an ID or address for an I2C mux may be used as the ID oraddress of the memory devices 2101.

FIG. 28 is a flowchart of a technique of communicating error informationaccording to an embodiment. In 2800, a read error in a memory deviceoccurs. In response, in 2802, the error is diagnosed. As will bedescribed in further detail, not only may the error be identified, butother corrective action make be taken to repair the error.

In 2804, the error information is reported. As described above, acommunication link between the memory device, other components of amemory module, and a processor may be used to communicate errorinformation. Reporting of the error information 2804 may use suchcommunication links.

FIG. 29 is a flowchart of a technique of handling errors according to anembodiment. This embodiment is an example of how a correctable error ishandled, for example, how a correctable error is handled by the ECCcontroller 1918 of FIG. 19. In particular, after a correctable error(CE) has occurred, a CE record is created in 2900. The CE record caninclude a variety of different information related to the error asdescribed above.

In 2902, the data is reread. In this embodiment, there are threepossible outcomes, no error occurs, a CE occurs, or an uncorrectableerror (UE) occurs in response to rereading the data. If no error occurs,in 2904 the error record is tagged as a soft-read error. If a CE occurs,the corrected data is rewritten in 2908. If an UE occurs, the errorrecord is updated to an uncorrectable error record in 2906.

As part of rewriting the corrected data in 2908, an error may occur. Ifno error occurs, in 2910 the error record is tagged as a soft-writeerror. If a UE occurs, the error record is updated to an uncorrectableerror record in 2906.

If a CE occurs, in 2912, a determination is made whether the memory cellis repairable. In a particular embodiment, a CE at this stage mayindicate that the error cannot be repaired by rewriting. Accordingly,the error may be caused by a hardware error. Depending on the outcome ofthe determining whether the memory cell is repairable in 2912, the errorrecord is further annotated and may be repaired. If the memory cell isrepairable, in 2914, the memory cell is repaired and the error is taggedas a hard error. If the memory cell is not repairable, in 2916, theerror record is tagged as an unrepairable hard error. Accordingly, bythe above described diagnosis, the error may be further categorizedand/or repaired.

Although rewriting in 2908 has been used as an example of an operationthat may indicate a UE, CE, or no error, such information may be theresult of other operations. For example, after rewriting the data in2908, a read may be performed and similar error information may begenerated.

FIG. 30 is a flowchart of a technique of handling errors according toanother embodiment. This embodiment is an example of how anuncorrectable error is handled, for example, how an uncorrectable erroris handled by the ECC controller 1918 of FIG. 19. In particular, afteran uncorrectable error has occurred, a UE record is created in 3000. Insome embodiments, the UE record may be a result of an update to a UErecord in 2906 as described with respect to FIG. 29.

In 3002, the data associated with the UE record may be reread. Inresponse, different operations may be performed. If a UE occurs afterrereading, in 3006, the record is tagged as an unrepairable error. If noerror occurs, the record is tagged as a soft-read error in 3004. If a CEoccurs, corrected data is rewritten in 3008. Similar to the rewriting in2908 of FIG. 29, the result generated from the operation may come fromother sources, such as rereading the data after rewriting.

In response to a result of rewriting the data, different operations maybe performed. If the result is a UE, the record is tagged as anunrepairable error in 3006. If no error occurs, the record is tagged asa soft-read and soft-write error in 3010.

If the result is a CE, in 3012, a determination is made whether thememory cell is repairable. If the memory cell is repairable, in 3014,the repair is performed and the record is tagged as a soft-read andrepairable hard error. If the memory cell is not repairable, in 3016,the record is tagged as a soft-read and unrepairable hard error.

Although various categorizations of errors have been described above, insome embodiments, all of such information may not be available externalto the memory device. For example, particular types of errors, such asthe soft-read and soft-write errors of FIG. 29 may be aggregated assoft-errors. Any aggregation, summarizing, or the like may be performedto generate error information to be transmitted from the memory device.Moreover, the memory device may be configurable to provide a particularlevel of detail.

In an embodiment, using techniques such as those described in FIGS. 29and 30, the memory device may be configured to perform error managementtechniques such as soft-error recovery (e.g. memory scrubbing),hard-error repair, or the like. Information related to such operationsmay also be available in the error information provided by a memorydevice.

In an embodiment, the above described operations may be performed aftera read has occurred. In particular, the operations may be configured tonot block a read operation. However, once an appropriate period occurs,such as a maintenance interval, a refresh cycle, or the like, the errorrecords may be processed, updated, memory cells repaired, or the like.

Although particular sequences of errors have been used as examples ofcriteria to categorize errors or repair memory cells, in otherembodiments, different sequences may be used. For example, referring toFIG. 29, in that embodiment, determining whether a memory cell isrepairable in 2910 occurs if a CE occurs, followed by CE when rereadingin 2902 and followed by a CE when rewriting in 2908. However, in otherembodiments, determining whether a memory cell is repairable in 2910 mayoccur only if the rereading in 2902 resulted in a CE after multiplerereading attempts. That is, in some embodiments, the particularcriteria to categorize the errors may be different that the examplesdescribed above.

Furthermore, although particular designations of error types have beenused, in some embodiments, all of such error types need not be used.Similarly, in some embodiments, different error types may be used.

FIG. 31 is a flowchart of a technique of communicating error informationaccording to an embodiment. In this embodiment, a read error whenreading data from a memory occurs in 3100. In response, errorinformation may be generated. For example, a read error may be acorrectable error that was corrected. The error information may beinformation about that correctable error. In another example, the readerror may be multiple errors. The error information may be informationabout those errors.

In 3102, a read error command is received. In an embodiment, a readerror command may be received by a memory module. If an error hasoccurred, the memory may transmit the error information in 3104. Beforereceiving a read error command in 3102, the memory module may storeerror information on errors that have occurred. That error informationregarding earlier errors may be transmitted in 3104 in response to theread error command. However, if an error has not occurred, thetransmission of error information in 3104 may be transmission ofinformation indicating that an error has not occurred.

As described above, error information may be transmitted over a bus. Inparticular, the bus may be an out-of-band path relative to a main datapath of the memory module. Accordingly, the transmitting in 3104 mayinclude transmitting the error information over the bus.

FIG. 24B is a flowchart of a technique of communicating errorinformation according to another embodiment. Referring to FIGS. 24A and24B, in an embodiment, the operations of FIG. 24B may be operations of acontroller. In particular, a read error command may be transmitted in2406 from the controller. The read error command transmitted in 2406 maybe the read error command received in 2402. As described above, in 2404,error information may be transmitted. That error information may bereceived at the controller in 2408. For example, a controller may beconfigured to poll a memory module. Thus, the controller may transmitthe read error command in 3106 and receive the error information at thecontroller in 3108. As described above, the controller may have amemory, such as non-volatile memory, in which the controller may storethe error information. At a later time, the error information may betransmitted to a processor in 3110.

Although the use of a controller to transmit the read error command hasbeen used as an example, in another embodiment, a processor may transmitthe read error command in 3106. That read error command may be receivedby the memory module in 3102 and the error information may betransmitted to the processor in 3110. That is, the error informationmay, but need not be received and/or processed in a controller.

FIG. 32 is a flowchart of a technique of communicating error informationaccording to another embodiment. Referring to FIGS. 28 and 32, and usingthe memory module 2100 as an example, in 3200, a communication isreceived through the module error interface 2138. In 3202, errorinformation is read from at least one memory device 2101.

In an embodiment, reading the error information in 3202 may be performedin response to the communication in 3200. However, in other embodimentsreading the error information may be performed at different times,including before receiving the communication. Regardless, errorinformation from the memory devices 2101 may be used to respond to thecommunication in 3204.

The reading of the error information in 3202 may be accomplished in avariety of ways. For example, each of the memory devices 2101 may beaccessed through a corresponding dedicated bus, such as in FIG. 24. Inanother embodiment, the each of the memory devices 2101 may be accessedthrough a common bus, such as in FIGS. 25A, 25B, or 26. In anotherembodiment, the communication may be forwarded on to one or more of thememory devices 2101, such as by the repeater 2750 of FIG. 27.

Although the memory module 2100 of FIG. 21 was used as an example, thetechniques described herein may be used by different memory modules,systems, or the like.

FIG. 33 is a flowchart of a technique of communicating error informationaccording to another embodiment. In this embodiment, a read error mayoccur in 3300. A read error command is transmitted to a controller in3312. For example, the controller may receive the read error commandfrom a processor. In 3314, a read error command is transmitted to amemory module. For example, the controller may forward the read errorcommand received from the processor on to the memory module, modify theread error command, create a different read error command for the memorymodule, or the like to transmit a read error command to the memorymodule in 3314. The read error command transmitted in 3314 may bereceived in 3302, and error information may be transmitted in 3304similar to operations 3102 and 3104 of FIG. 31A, respectively. Errorinformation may be propagated to the processor as described above.

As described above, a controller may poll a memory module for errorinformation and store that error information. Accordingly, when a readerror command is received by a controller from a processor, thecontroller may already have read error information. The controller maytransmit the stored error information to the processor. The controllermay, but need not poll the memory module for more error informationbefore the controller transmits the stored error information to theprocessor.

FIG. 34 is a flowchart of a technique of communicating error informationaccording to another embodiment. In an embodiment, a processor maytransmit a read error command in 3400. In response, the processor mayreceive error information in 3402. In 3406, the processor may combinethe error information with additional information. As described above,additional information may be any information, such as a status of theprocessor, peripherals, busses, or the like, including informationunrelated to the memory module. In a particular example, the processormay combine the error information with information from a MCA module.

In a particular embodiment, in 3408, the combined information may beprovided to an EDAC module. As described above, the EDAC module may makeinformation regarding errors of various systems available to higherlevel applications.

FIG. 35 is a schematic view of a system with a memory systemarchitecture according to an embodiment. In this embodiment, the system3500 includes a processor 3504 and software 3510 similar to theprocessor 104 and software 110 of FIG. 1. However, in this embodiment,the system 3500 includes a memory 3502 and an error correction circuit3568.

In this embodiment, the memory 3502 is not configured to correct errors.The memory is coupled to the error correction circuit 3568 and isconfigured to transmit data to the error correction circuit throughcommunication path 3572.

The error correction circuit 3568 is configured to correct errors indata received from the memory 3502. The error correction circuit 3568 iscoupled to the processor 3504 through a second communication path 3570and a third communication path 3508. The second communication path 3570is the main path through which the processor 3504 is configured toreceive data. For example, the second communication path 3570 may be asystem bus for the processor 3504.

In contrast, the third communication path 3508 is similar to thecommunication path 108 or the like described above. That is, the thirdcommunication path 3508 may be a separate, out-of-band communicationpath, include a controller 3514, or have other variations similar to thecommunication paths described above.

FIG. 36 is a schematic view of a server according to an embodiment. Inthis embodiment, the server 3600 may include a stand-alone server, arack-mounted server, a blade server, or the like. The server 3600includes a memory 3602, a processor 3604, and a BMC 3614. The processor3604 is coupled to the memory 3602 through the communication path 3606.The BMC is coupled to the processor 3604 through the bus 3616 andcoupled to the memory 3602 through the bus 3612. The memory 3602,processor 3604, BMC 3614, communication path 3606, and busses 3612 and3616 may be any of the above described corresponding components.

FIG. 37 is a schematic view of a server system according to anembodiment. In this embodiment, the server system 3700 includes multipleservers 3702-1 to 3702-N. The servers 3702 are each coupled to a manager3704. One or more of the servers 3702 may be similar to the server 3500described above. In addition, the manager 3704 may include a system witha memory system architecture as described above.

The manager 3704 is configured to manage the servers 3702 and othercomponents of the server system 3700. For example, the manager 3704 maybe configured to manage the configurations of the servers 3702. Eachserver 3702 is configured to communicate error information to themanager 3704. The error information may include correctible errorinformation communicated to a processor in one of the servers 3702 asdescribed above or other error information based on the correctibleerror information. The manager 3704 may be configured to take actionsbased on that error information. For example, server 3702-1 may have anumber of correctible errors that exceeds a threshold. The manager 3704may be configured to transfer the functions of that server 3702-1 toserver 3702-2 and shutdown server 3702-1 for maintenance and/orreplacement. Although a particular example has been given, the manager3704 may be configured to take other actions based on the errorinformation.

FIG. 38 is a schematic view of a data center according to an embodiment.In this embodiment, the data center 3800 includes multiple serverssystems 3802-1 to 3802-N. The server systems 3802 may be similar to theserver system 3600 described above in FIG. 36. The server systems 3802are coupled to a network 3804, such as the Internet. Accordingly, theserver systems 3802 may communicate through the network 3804 withvarious nodes 3806-1 to 3806-M. For example, the nodes 3806 may beclient computers, other servers, remote data centers, storage systems,or the like.

An embodiment includes a system, comprising: a memory configured tostore data, correct an error in data read from the stored data, andgenerate error information in response to the correcting of the error inthe data read from the stored data; and a processor coupled to thememory through a first communication path and a second communicationpath and configured to: receive data from the memory through the firstcommunication path; and receive the error information from the memorythrough the second communication path.

In an embodiment, the error is a single-bit error; and the errorinformation indicates that an error was corrected.

In an embodiment, the error information includes corrected errorinformation; and the processor is configured to receive the correctederror information through a path other than the first communicationpath.

In an embodiment, the memory is a dynamic random access memory module.

In an embodiment, the system further comprises: a controller coupled tothe processor and the memory and configured to communicate with theprocessor and the memory. The controller is part of the secondcommunication path.

In an embodiment, the controller is a baseboard management controller.

In an embodiment, the controller is coupled to the processor by aninterface compliant with intelligent platform management interface(IPMI).

In an embodiment, the controller is coupled to the memory by aninterface compliant with System Management Bus (SMBus).

In an embodiment, the controller is configured to: store the errorinformation; and provide the error information to the processor inresponse to a request received from the processor.

In an embodiment, the processor includes a memory controller coupled tothe memory; and the memory controller is coupled to the memory throughthe first communication path.

In an embodiment, the processor includes a memory controller coupled tothe memory; and the memory controller is not configured to correcterrors in data read from the memory.

In an embodiment, the first communication path includes a plurality ofdata lines and at least one data strobe line; and the memory isconfigured to communicate an uncorrectable error by a signal transmittedover the at least one data strobe line.

In an embodiment, the system further comprises: a third communicationpath coupled between the memory and the processor. The memory isconfigured to communicate an uncorrectable error over the thirdcommunication path.

In an embodiment, the processor is configured to request the errorinformation generated by the memory.

In an embodiment, the processor is configured to combine the errorinformation with other information associated with the memory.

In an embodiment, the other information is based on information receivedthrough the first communication path.

In an embodiment, the processor includes an interface coupled to thesecond communication path; and the processor is further configured to:receive the error information through the interface; and receive otherinformation through the interface.

In an embodiment, the memory includes at least one of a serial presencedetect system and a registering clock driver system; and the otherinformation is received from the at least one of the serial presencedetect system and the registering clock driver system.

An embodiment includes a memory module, comprising: at least one memorydevice configured to store data; a first interface; and a secondinterface. The first interface is configured to transmit data stored inthe at least one memory device; and the second interface is configuredto transmit error information generated in response to correcting anerror in data read from the at least one memory device.

In an embodiment, the second interface includes at least one of a serialpresence detect interface and a registering clock driver interface.

In an embodiment, the memory module further comprises a controllercoupled to the first interface and configured to modify a data strobesignal transmitted through the first interface in response to detectingan uncorrectable error.

In an embodiment, the second interface is further configured to transmiterror information in response to detecting an uncorrectable error.

An embodiment includes a method, comprising: reading, at a memorymodule, data including an error; generating error information based onreading the data including the error; receiving, at memory module, acommand to read the error information; and transmitting, from the memorymodule, the error information in response to the command.

In an embodiment, the method further comprises receiving, at acontroller, the error information; and transmitting, from the controllerto a processor, the error information.

In an embodiment, the method further comprises: transmitting, from acontroller, the command to read error information; and receiving, at thecontroller, the error information.

In an embodiment, the command to read error information is referred toas a first command to read error information, the method furthercomprising: receiving, from a processor at a controller, a secondcommand to read error information; and transmitting, from thecontroller, the first command in response to the second command.

In an embodiment, the method further comprises communicating, from thememory module, an uncorrectable error by modifying a data strobe signal.

In an embodiment, the method further comprises generating, at aprocessor, additional information associated with the memory module; andcombining, at the processor, the additional information with the errorinformation.

In an embodiment, transmitting, from the memory module, the errorinformation comprises transmitting the error information and otherinformation over a communication link.

In an embodiment, the other information is unrelated to the memorymodule.

An embodiment includes a system, comprising: a memory; a processorcoupled to the memory through a main memory channel; and a communicationlink separate from the main memory channel and coupled to the memory andthe processor; wherein the memory and processor are configured tocommunicate with each other through the main memory channel and thecommunication link.

In an embodiment, the processor comprises a memory controller; and thememory controller is part of main memory channel.

In an embodiment, the processor is configured to receive systemmanagement information through the communication link.

In an embodiment, the system management information comprises at leastone of thermal information and power information.

In an embodiment, the memory is configured to communicate errorinformation to the processor through the communication link.

An embodiment includes system, comprising: a memory without errorcorrection; an error correction circuit coupled to the memory,configured to correct an error in data read from the memory, andconfigured to generate error information in response to the error; and aprocessor coupled to the error correction circuit through a firstcommunication path and a second communication path. The processor isconfigured to receive corrected data from the error correction circuitthrough the first communication path; and the processor is configured toreceive the error information from the error correction circuit throughthe second communication path.

In an embodiment, the second communication path includes a controllerconfigured to receive the error information from the error correctioncircuit and transmit the error information to the processor.

An embodiment includes a method, comprising: reading, at a memorydevice, data including an error in response to a read command receivedthrough a data interface; recording error information based on readingthe data including the error; and transmitting, from the memory module,the error information through a error interface.

In an embodiment, the method further comprises rereading the data readfrom memory in response to the error and identifying the error inresponse to rereading the data.

In an embodiment, the method further comprises identifying the error asuncorrectable if the reread data indicates an uncorrectable error.

In an embodiment, the method further comprises identifying the error asunrepairable if the reread data indicates an uncorrectable error and theerror was an uncorrectable error.

In an embodiment, the method further comprises identifying the error asa soft-read error if the reread data indicates no error.

In an embodiment, the method further comprises rewriting corrected datato the memory in response to the error being a correctable error.

In an embodiment, the method further comprises if an uncorrectable erroroccurs during the rewrite, identifying the error as an uncorrectableerror.

In an embodiment, the method further comprises if no error occurs duringthe rewrite, identifying the error as a soft-write error.

In an embodiment, the method further comprises if a correctable erroroccurs during the rewrite, attempting to repair the memory.

In an embodiment, the method further comprises identifying the errorbased on the outcome of the attempt to repair the memory.

In an embodiment, the method further comprises communicating, from thememory module, an uncorrectable error by modifying a data strobe signal.

An embodiment includes a memory module, comprising: a data interface; anerror interface; a plurality of memory devices, each memory devicecoupled to the data interface and the error interface and comprising: amemory configured to store data; a controller coupled to the datainterface, the error interface, and the memory; wherein: the controlleris configured to transmit data stored in the memory through the datainterface; and the controller is configured to transmit errorinformation generated in response to correcting an error in data readfrom memory through the error interface.

In an embodiment, the error interface is configured to aggregate errorinformation from the memory devices.

In an embodiment, for each memory device, the controller is configuredto modify a data strobe signal transmitted from the memory device to thedata interface in response to detecting an uncorrectable error; and thedata interface is configured to transmit a data strobe signal inresponse to a modified data strobe signal from one or more of the memorydevices.

An embodiment includes a memory device, comprising: a memory configuredto store data; a controller coupled to the memory and configured to:read data stored in the memory; diagnose an error in the data read fromthe memory; and identify an error type of the error in response todiagnosing the error.

In an embodiment, the controller is configured to identify the errortype as at least one of a soft-read error, a soft-write error, a harderror, a repairable error, and an unrepairable error.

In an embodiment, the controller is configured to diagnose the error inresponse to rereading the data.

In an embodiment, the controller is configured to diagnose the error inresponse to rewriting the data.

In an embodiment, the controller is configured to determine whether torepair the memory in response to rewriting the data.

Although the structures, methods, and systems have been described inaccordance with exemplary embodiments, one of ordinary skill in the artwill readily recognize that many variations to the disclosed embodimentsare possible, and any variations should therefore be considered to bewithin the spirit and scope of the apparatus, method, and systemdisclosed herein. Accordingly, many modifications may be made by one ofordinary skill in the art without departing from the spirit and scope ofthe appended claims.

1. A system, comprising: a memory configured to store data, correct anerror in data read from the stored data, and generate error informationin response to correcting the error in the data read from the storeddata; and a processor coupled to the memory through a firstcommunication path and a second communication path, the firstcommunication path being part of a main memory path and the secondcommunication path being part of a system control path, the secondcommunication path being separate from the first communication path, theprocessor being configured to: receive the data read from the storeddata and send the received read data through the first communicationpath; and receive the error information from the memory and send theerror information through the second communication path.
 2. The systemof claim 1, wherein the memory is a dynamic random access memory module.3. The system of claim 1, wherein the second communication pathcomprises an out-of-band communication path with respect to the firstcommunication path.
 4. The system of claim 1, wherein the secondcommunication path comprises a platform management bus.
 5. The system ofclaim 4, wherein the platform management bus comprises a systemmanagement bus (SMBus), an inter-integrated circuit (1²C) bus, anintelligent platform management interface (IPMI) bus, or a Modbus. 6.The system of claim 1, wherein the second communication path issubstantially slower than the first communication path.
 7. The system ofclaim 1, wherein the first communication path comprises a first datarate and the second communication path comprises a second data rate, thesecond data rate being less than or equal to 1/10 of the first datarate.
 8. The system of claim 1, wherein the processor receives a pollfor error information through the second communication path.
 9. Thesystem of claim 1, wherein the processor is further configured to pusherror information through the second communication path.
 10. The systemof claim 1, further comprising: a controller coupled to the processorthrough the second communication path.
 11. The system of claim 10,wherein the controller is a baseboard management controller.
 12. Thesystem of claim 10, wherein the controller is configured to: store theerror information; and provide the error information to the processor inresponse to a request received from the processor.
 13. A method,comprising: reading data stored in a memory module through a main memorychannel; generating, at the memory module, error information relating toan error in the read data; receiving at the memory module through asystem control channel a command to read the error information, thesystem control channel being separate from the main memory channel; andtransmitting from the memory module the error information through thesystem control channel in response to the command.
 14. The method ofclaim 13, wherein the system control channel comprises an out-of-bandcommunication path with respect to the main memory channel.
 15. Themethod of claim 13, wherein the system control channel comprises aplatform management bus.
 16. A system, comprising: a memory; a processorcoupled to the memory through a main memory channel; and a systemcontrol channel that is separate from the main memory channel, thesystem control channel being coupled to the memory and the processor;wherein: the memory and processor are configured to communicate witheach other through the main memory channel and the system controlchannel; and the memory is configured to communicate error informationto the processor through the system control channel.
 17. The system ofclaim 16, wherein the processor is configured to receive systemmanagement information through the system control channel.
 18. Thesystem of claim 16, wherein the system control channel comprises anout-of-band communication path with respect to the main memory channel.19. The system of claim 16, wherein the system control channel comprisesa platform management bus.
 20. The system of claim 19, wherein theplatform management bus comprises a system management bus (SMBus), aninter-integrated circuit (1²C) bus, an intelligent platform managementinterface (IPMI) bus, or a Modbus.